13.cpp

#include <iostream>
#include <string>
#include <map>
using namespace std;

class Solution
{
public:
    int romanToInt(string s)
    {
        map<char, int> map = {{'I', 1}, {'V', 5}, {'X', 10}, {'L', 50}, {'C', 100}, {'D', 500}, {'M', 1000}};

        int total = 0;
        int previous = 0;

        for (int i = s.size() - 1; i >= 0; i--)
        {
            int value = map[s[i]];
            if (value < previous)
                total -= value;
            else
                total += value;

            previous = map[s[i]];
        }
        return total;
    }
};

int main(){
    string s;    
    cin >> s;
    Solution sol;
    cout << sol.romanToInt(s) << endl;

};